Roll SwiftShader from 9b300a6d6747 to 4e40d502c440 (2 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/9b300a6d6747..4e40d502c440

2023-09-11 dneto@google.com Avoid "var set but not used" warnings in
math tests
2023-09-11 syoussefi@google.com Update Vulkan headers to version 1.3.238

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-angle-autoroll
Please CC angle-team@google.com,ianelliott@google.com on the revert to
ensure that a human
is aware of the problem.

To file a bug in SwiftShader:
https://bugs.chromium.org/p/swiftshader/issues/entry
To file a bug in ANGLE:
https://bugs.chromium.org/p/angleproject/issues/entry

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Bug: angleproject:8341
Tbr: ianelliott@google.com
Use-Permissive-Angle-Pixel-Comparison: True
Change-Id: I2c9927be3afdbc1e7c1e2257823936a95279bed7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4857934
Commit-Queue: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -651,7 +651,7 @@ deps = {
   },
 
   'third_party/SwiftShader': {
-    'url': Var('swiftshader_git') + '/SwiftShader@9b300a6d6747be57610964ca01289c9d01995674',
+    'url': Var('swiftshader_git') + '/SwiftShader@4e40d502c440cc59b25fa3a5fee0eadbab7442aa',
     'condition': 'not build_with_chromium',
   },